why is my spiritual health so tied to my physical health?

like when I dont work out, I actually become unpleasant to be around (to myself... in my head... i know... its messed up)... and then my spiritual walk deteriorates...is it just discipline will cover all areas when i get down on it?

Physical exercise changes your blood chemistry and can have a positive affect on mood. Dramatically so in some cases if one is suffering from depression due to chemical imbalances. If you want to find some research to support this, you should be able to find some here.